/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package javax.servlet;

import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Enumeration;
import java.util.EventListener;
import java.util.Map;
import java.util.Set;

import javax.servlet.descriptor.JspConfigDescriptor;

/**
 * Defines a set of methods that a servlet uses to communicate with its servlet container, for
 * example, to get the MIME type of a file, dispatch requests, or write to a log file.
 * <p>
 * There is one context per "web application" per Java Virtual Machine. (A "web application" is a
 * collection of servlets and content installed under a specific subset of the server's URL
 * namespace such as <code>/catalog</code> and possibly installed via a <code>.war</code> file.)
 * <p>
 * In the case of a web application marked "distributed" in its deployment descriptor, there will be
 * one context instance for each virtual machine. In this situation, the context cannot be used as a
 * location to share global information (because the information won't be truly global). Use an
 * external resource like a database instead.
 * <p>
 * The <code>ServletContext</code> object is contained within the {@link ServletConfig} object,
 * which the Web server provides the servlet when the servlet is initialized.
 *
 * @see Servlet#getServletConfig
 * @see ServletConfig#getServletContext
 */
public interface ServletContext {

    public static final String TEMPDIR = "javax.servlet.context.tempdir";

    /**
     * @since Servlet 3.0
     */
    public static final String ORDERED_LIBS = "javax.servlet.context.orderedLibs";

    /**
     * Return the main path associated with this context.
     *
     * @return The main context path
     * @since Servlet 2.5
     */
    public String getContextPath();

    /**
     * Returns a <code>ServletContext</code> object that corresponds to a specified URL on the
     * server.
     * <p>
     * This method allows servlets to gain access to the context for various parts of the server, and
     * as needed obtain {@link RequestDispatcher} objects from the context. The given path must be
     * begin with "/", is interpreted relative to the server's document root and is matched against
     * the context roots of other web applications hosted on this container.
     * <p>
     * In a security conscious environment, the servlet container may return
     * <code>null</code> for a given URL.
     *
     * @param uripath a <code>String</code> specifying the context path of another web application in
     * the container.
     * @return the <code>ServletContext</code> object that corresponds to the named URL, or null if
     * either none exists or the container wishes to restrict this access.
     * @see RequestDispatcher
     */
    public ServletContext getContext(String uripath);

    /**
     * Returns the major version of the Java Servlet API that this servlet container supports. All
     * implementations that comply with Version 3.1 must have this method return the integer 3.
     *
     * @return 3
     */
    public int getMajorVersion();

    /**
     * Returns the minor version of the Servlet API that this servlet container supports. All
     * implementations that comply with Version 3.1 must have this method return the integer 1.
     *
     * @return 1
     */
    public int getMinorVersion();

    /**
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0 TODO SERVLET3 - Add comments
     */
    public int getEffectiveMajorVersion();

    /**
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0 TODO SERVLET3 - Add comments
     */
    public int getEffectiveMinorVersion();

    /**
     * Returns the MIME type of the specified file, or <code>null</code> if the MIME type is not
     * known. The MIME type is determined by the configuration of the servlet container, and may be
     * specified in a web application deployment descriptor. Common MIME types are
     * <code>"text/html"</code> and
     * <code>"image/gif"</code>.
     *
     * @param file a <code>String</code> specifying the name of a file
     * @return a <code>String</code> specifying the file's MIME type
     */
    public String getMimeType(String file);

    /**
     * Returns a directory-like listing of all the paths to resources within the web application whose
     * longest sub-path matches the supplied path argument. Paths indicating subdirectory paths end
     * with a '/'. The returned paths are all relative to the root of the web application and have a
     * leading '/'. For example, for a web application containing<br>
     * <br>
     * /welcome.html<br> /catalog/index.html<br> /catalog/products.html<br>
     * /catalog/offers/books.html<br> /catalog/offers/music.html<br> /customer/login.jsp<br>
     * /WEB-INF/web.xml<br> /WEB-INF/classes/com.acme.OrderServlet.class,<br>
     * <br>
     * getResourcePaths("/") returns {"/welcome.html", "/catalog/", "/customer/", "/WEB-INF/"}<br>
     * getResourcePaths("/catalog/") returns {"/catalog/index.html", "/catalog/products.html",
     * "/catalog/offers/"}.<br>
     *
     * @param path the partial path used to match the resources, which must start with a /
     * @return a Set containing the directory listing, or null if there are no resources in the web
     * application whose path begins with the supplied path.
     * @since Servlet 2.3
     */
    public Set<String> getResourcePaths(String path);

    /**
     * Returns a URL to the resource that is mapped to a specified path. The path must begin with a
     * "/" and is interpreted as relative to the current context root.
     * <p>
     * This method allows the servlet container to make a resource available to servlets from any
     * source. Resources can be located on a local or remote file system, in a database, or in a
     * <code>.war</code> file.
     * <p>
     * The servlet container must implement the URL handlers and
     * <code>URLConnection</code> objects that are necessary to access the
     * resource.
     * <p>
     * This method returns <code>null</code> if no resource is mapped to the pathname.
     * <p>
     * Some containers may allow writing to the URL returned by this method using the methods of the
     * URL class.
     * <p>
     * The resource content is returned directly, so be aware that requesting a
     * <code>.jsp</code> page returns the JSP source code. Use a
     * <code>RequestDispatcher</code> instead to include results of an
     * execution.
     * <p>
     * This method has a different purpose than
     * <code>java.lang.Class.getResource</code>, which looks up resources based
     * on a class loader. This method does not use class loaders.
     *
     * @param path a <code>String</code> specifying the path to the resource
     * @return the resource located at the named path, or <code>null</code> if there is no resource at
     * that path
     * @throws MalformedURLException if the pathname is not given in the correct form
     */
    public URL getResource(String path) throws MalformedURLException;

    /**
     * Returns the resource located at the named path as an
     * <code>InputStream</code> object.
     * <p>
     * The data in the <code>InputStream</code> can be of any type or length. The path must be
     * specified according to the rules given in
     * <code>getResource</code>. This method returns <code>null</code> if no
     * resource exists at the specified path.
     * <p>
     * Meta-information such as content length and content type that is available via
     * <code>getResource</code> method is lost when using this method.
     * <p>
     * The servlet container must implement the URL handlers and
     * <code>URLConnection</code> objects necessary to access the resource.
     * <p>
     * This method is different from
     * <code>java.lang.Class.getResourceAsStream</code>, which uses a class
     * loader. This method allows servlet containers to make a resource available to a servlet from
     * any location, without using a class loader.
     *
     * @param path a <code>String</code> specifying the path to the resource
     * @return the <code>InputStream</code> returned to the servlet, or
     * <code>null</code> if no resource exists at the specified path
     */
    public InputStream getResourceAsStream(String path);

    /**
     * Returns a {@link RequestDispatcher} object that acts as a wrapper for the resource located at
     * the given path. A <code>RequestDispatcher</code> object can be used to forward a request to the
     * resource or to include the resource in a response. The resource can be dynamic or static.
     * <p>
     * The pathname must begin with a "/" and is interpreted as relative to the current context root.
     * Use <code>getContext</code> to obtain a
     * <code>RequestDispatcher</code> for resources in foreign contexts. This
     * method returns <code>null</code> if the <code>ServletContext</code> cannot return a
     * <code>RequestDispatcher</code>.
     *
     * @param path a <code>String</code> specifying the pathname to the resource
     * @return a <code>RequestDispatcher</code> object that acts as a wrapper for the resource at the
     * specified path, or <code>null</code> if the
     * <code>ServletContext</code> cannot return a
     * <code>RequestDispatcher</code>
     * @see RequestDispatcher
     * @see ServletContext#getContext
     */
    public RequestDispatcher getRequestDispatcher(String path);

    /**
     * Returns a {@link RequestDispatcher} object that acts as a wrapper for the named servlet.
     * <p>
     * Servlets (and JSP pages also) may be given names via server administration or via a web
     * application deployment descriptor. A servlet instance can determine its name using {@link
     * ServletConfig#getServletName}.
     * <p>
     * This method returns <code>null</code> if the <code>ServletContext</code> cannot return a
     * <code>RequestDispatcher</code> for any reason.
     *
     * @param name a <code>String</code> specifying the name of a servlet to wrap
     * @return a <code>RequestDispatcher</code> object that acts as a wrapper for the named servlet,
     * or <code>null</code> if the
     * <code>ServletContext</code> cannot return a
     * <code>RequestDispatcher</code>
     * @see RequestDispatcher
     * @see ServletContext#getContext
     * @see ServletConfig#getServletName
     */
    public RequestDispatcher getNamedDispatcher(String name);

    /**
     * Do not use. This method was originally defined to retrieve a servlet from a
     * <code>ServletContext</code>. In this version, this method always returns <code>null</code> and
     * remains only to preserve binary compatibility. This method will be permanently removed in a
     * future version of the Java Servlet API.
     * <p>
     * In lieu of this method, servlets can share information using the
     * <code>ServletContext</code> class and can perform shared business logic
     * by invoking methods on common non-servlet classes.
     *
     * @param name Not used
     * @return Always <code>null</code>
     * @throws ServletException never
     * @deprecated As of Java Servlet API 2.1, with no direct replacement.
     */
    @SuppressWarnings("dep-ann")
    // Spec API does not use @Deprecated
    public Servlet getServlet(String name) throws ServletException;

    /**
     * Do not use. This method was originally defined to return an
     * <code>Enumeration</code> of all the servlets known to this servlet
     * context. In this version, this method always returns an empty enumeration and remains only to
     * preserve binary compatibility. This method will be permanently removed in a future version of
     * the Java Servlet API.
     *
     * @return Always and empty Enumeration
     * @deprecated As of Java Servlet API 2.0, with no replacement.
     */
    @SuppressWarnings("dep-ann")
    // Spec API does not use @Deprecated
    public Enumeration<Servlet> getServlets();

    /**
     * Do not use. This method was originally defined to return an
     * <code>Enumeration</code> of all the servlet names known to this context.
     * In this version, this method always returns an empty
     * <code>Enumeration</code> and remains only to preserve binary
     * compatibility. This method will be permanently removed in a future version of the Java Servlet
     * API.
     *
     * @return Always and empty Enumeration
     * @deprecated As of Java Servlet API 2.1, with no replacement.
     */
    @SuppressWarnings("dep-ann")
    // Spec API does not use @Deprecated
    public Enumeration<String> getServletNames();

    /**
     * Writes the specified message to a servlet log file, usually an event log. The name and type of
     * the servlet log file is specific to the servlet container.
     *
     * @param msg a <code>String</code> specifying the message to be written to the log file
     */
    public void log(String msg);

    /**
     * Do not use.
     *
     * @param exception The exception to log
     * @param msg The message to log with the exception
     * @deprecated As of Java Servlet API 2.1, use {@link #log(String message, Throwable throwable)}
     * instead.
     * <p>
     * This method was originally defined to write an exception's stack trace and an explanatory error
     * message to the servlet log file.
     */
    @SuppressWarnings("dep-ann")
    // Spec API does not use @Deprecated
    public void log(Exception exception, String msg);

    /**
     * Writes an explanatory message and a stack trace for a given
     * <code>Throwable</code> exception to the servlet log file. The name and
     * type of the servlet log file is specific to the servlet container, usually an event log.
     *
     * @param message a <code>String</code> that describes the error or exception
     * @param throwable the <code>Throwable</code> error or exception
     */
    public void log(String message, Throwable throwable);

    /**
     * Returns a <code>String</code> containing the real path for a given virtual path. For example,
     * the path "/index.html" returns the absolute file path on the server's filesystem would be
     * served by a request for "http://host/contextPath/index.html", where contextPath is the context
     * path of this ServletContext..
     * <p>
     * The real path returned will be in a form appropriate to the computer and operating system on
     * which the servlet container is running, including the proper path separators. This method
     * returns <code>null</code> if the servlet container cannot translate the virtual path to a real
     * path for any reason (such as when the content is being made available from a
     * <code>.war</code> archive).
     *
     * @param path a <code>String</code> specifying a virtual path
     * @return a <code>String</code> specifying the real path, or null if the translation cannot be
     * performed
     */
    public String getRealPath(String path);

    /**
     * Returns the name and version of the servlet container on which the servlet is running.
     * <p>
     * The form of the returned string is
     * <i>servername</i>/<i>versionnumber</i>. For example, the JavaServer Web
     * Development Kit may return the string
     * <code>JavaServer Web Dev Kit/1.0</code>.
     * <p>
     * The servlet container may return other optional information after the primary string in
     * parentheses, for example,
     * <code>JavaServer Web Dev Kit/1.0 (JDK 1.1.6; Windows NT 4.0 x86)</code>.
     *
     * @return a <code>String</code> containing at least the servlet container name and version number
     */
    public String getServerInfo();

    /**
     * Returns a <code>String</code> containing the value of the named context-wide initialization
     * parameter, or <code>null</code> if the parameter does not exist.
     * <p>
     * This method can make available configuration information useful to an entire "web application".
     * For example, it can provide a webmaster's email address or the name of a system that holds
     * critical data.
     *
     * @param name a <code>String</code> containing the name of the parameter whose value is
     * requested
     * @return a <code>String</code> containing the value of the initialization parameter
     * @throws NullPointerException If the provided parameter name is
     * <code>null</code>
     * @see ServletConfig#getInitParameter
     */
    public String getInitParameter(String name);

    /**
     * Returns the names of the context's initialization parameters as an
     * <code>Enumeration</code> of <code>String</code> objects, or an empty
     * <code>Enumeration</code> if the context has no initialization parameters.
     *
     * @return an <code>Enumeration</code> of <code>String</code> objects containing the names of the
     * context's initialization parameters
     * @see ServletConfig#getInitParameter
     */

    public Enumeration<String> getInitParameterNames();

    /**
     * Set the given initialisation parameter to the given value.
     *
     * @param name Name of initialisation parameter
     * @param value Value for initialisation parameter
     * @return <code>true</code> if the call succeeds or <code>false</code> if
     * the call fails because an initialisation parameter with the same name has already been set
     * @throws IllegalStateException If initialisation of this ServletContext has already completed
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws NullPointerException If the provided parameter name is
     * <code>null</code>
     * @since Servlet 3.0
     */
    public boolean setInitParameter(String name, String value);

    /**
     * Returns the servlet container attribute with the given name, or
     * <code>null</code> if there is no attribute by that name. An attribute
     * allows a servlet container to give the servlet additional information not already provided by
     * this interface. See your server documentation for information about its attributes. A list of
     * supported attributes can be retrieved using <code>getAttributeNames</code>.
     * <p>
     * The attribute is returned as a <code>java.lang.Object</code> or some subclass. Attribute names
     * should follow the same convention as package names. The Java Servlet API specification reserves
     * names matching
     * <code>java.*</code>, <code>javax.*</code>, and <code>sun.*</code>.
     *
     * @param name a <code>String</code> specifying the name of the attribute
     * @return an <code>Object</code> containing the value of the attribute, or
     * <code>null</code> if no attribute exists matching the given name
     * @throws NullPointerException If the provided attribute name is
     * <code>null</code>
     * @see ServletContext#getAttributeNames
     */
    public Object getAttribute(String name);

    /**
     * Returns an <code>Enumeration</code> containing the attribute names available within this
     * servlet context. Use the {@link #getAttribute} method with an attribute name to get the value
     * of an attribute.
     *
     * @return an <code>Enumeration</code> of attribute names
     * @see #getAttribute
     */
    public Enumeration<String> getAttributeNames();

    /**
     * Binds an object to a given attribute name in this servlet context. If the name specified is
     * already used for an attribute, this method will replace the attribute with the new to the new
     * attribute.
     * <p>
     * If listeners are configured on the <code>ServletContext</code> the container notifies them
     * accordingly.
     * <p>
     * If a null value is passed, the effect is the same as calling
     * <code>removeAttribute()</code>.
     * <p>
     * Attribute names should follow the same convention as package names. The Java Servlet API
     * specification reserves names matching
     * <code>java.*</code>, <code>javax.*</code>, and <code>sun.*</code>.
     *
     * @param name a <code>String</code> specifying the name of the attribute
     * @param object an <code>Object</code> representing the attribute to be bound
     * @throws NullPointerException If the provided attribute name is
     * <code>null</code>
     */
    public void setAttribute(String name, Object object);

    /**
     * Removes the attribute with the given name from the servlet context. After removal, subsequent
     * calls to {@link #getAttribute} to retrieve the attribute's value will return
     * <code>null</code>.
     * <p>
     * If listeners are configured on the <code>ServletContext</code> the container notifies them
     * accordingly.
     *
     * @param name a <code>String</code> specifying the name of the attribute to be removed
     */
    public void removeAttribute(String name);

    /**
     * Returns the name of this web application corresponding to this ServletContext as specified in
     * the deployment descriptor for this web application by the display-name element.
     *
     * @return The name of the web application or null if no name has been declared in the deployment
     * descriptor.
     * @since Servlet 2.3
     */
    public String getServletContextName();

    /**
     * Register a servlet implementation for use in this ServletContext.
     *
     * @param servletName The name of the servlet to register
     * @param className The implementation class for the servlet
     * @return The registration object that enables further configuration
     * @throws IllegalStateException If the context has already been initialised
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public ServletRegistration.Dynamic addServlet(String servletName, String className);

    /**
     * Register a servlet instance for use in this ServletContext.
     *
     * @param servletName The name of the servlet to register
     * @param servlet The Servlet instance to register
     * @return The registration object that enables further configuration
     * @throws IllegalStateException If the context has already been initialised
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public ServletRegistration.Dynamic addServlet(String servletName, Servlet servlet);

    /**
     * Add servlet to context.
     *
     * @param servletName Name of servlet to add
     * @param servletClass Class of servlet to add
     * @return <code>null</code> if the servlet has already been fully defined,
     * else a {@link javax.servlet.ServletRegistration.Dynamic} object that can be used to further
     * configure the servlet
     * @throws IllegalStateException If the context has already been initialised
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public ServletRegistration.Dynamic addServlet(String servletName, Class<? extends Servlet> servletClass);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param <T> TODO
     * @param c TODO
     * @return TODO
     * @throws ServletException TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public <T extends Servlet> T createServlet(Class<T> c) throws ServletException;

    /**
     * Obtain the details of the named servlet.
     *
     * @param servletName The name of the Servlet of interest
     * @return The registration details for the named Servlet or
     * <code>null</code> if no Servlet has been registered with the
     * given name
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public ServletRegistration getServletRegistration(String servletName);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public Map<String, ? extends ServletRegistration> getServletRegistrations();

    /**
     * Add filter to context.
     *
     * @param filterName Name of filter to add
     * @param className Name of filter class
     * @return <code>null</code> if the filter has already been fully defined,
     * else a {@link javax.servlet.FilterRegistration.Dynamic} object that can be used to further
     * configure the filter
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws IllegalStateException If the context has already been initialised
     * @since Servlet 3.0
     */
    public FilterRegistration.Dynamic addFilter(String filterName, String className);

    /**
     * Add filter to context.
     *
     * @param filterName Name of filter to add
     * @param filter Filter to add
     * @return <code>null</code> if the filter has already been fully defined,
     * else a {@link javax.servlet.FilterRegistration.Dynamic} object that can be used to further
     * configure the filter
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws IllegalStateException If the context has already been initialised
     * @since Servlet 3.0
     */
    public FilterRegistration.Dynamic addFilter(String filterName, Filter filter);

    /**
     * Add filter to context.
     *
     * @param filterName Name of filter to add
     * @param filterClass Class of filter to add
     * @return <code>null</code> if the filter has already been fully defined,
     * else a {@link javax.servlet.FilterRegistration.Dynamic} object that can be used to further
     * configure the filter
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws IllegalStateException If the context has already been initialised
     * @since Servlet 3.0
     */
    public FilterRegistration.Dynamic addFilter(String filterName, Class<? extends Filter> filterClass);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param <T> TODO
     * @param c TODO
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws ServletException TODO
     * @since Servlet 3.
     */
    public <T extends Filter> T createFilter(Class<T> c) throws ServletException;

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param filterName TODO
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public FilterRegistration getFilterRegistration(String filterName);

    /**
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0 TODO SERVLET3 - Add comments
     */
    public Map<String, ? extends FilterRegistration> getFilterRegistrations();

    /**
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0 TODO SERVLET3 - Add comments
     */
    public SessionCookieConfig getSessionCookieConfig();

    /**
     * Configures the available session tracking modes for this web application.
     *
     * @param sessionTrackingModes The session tracking modes to use for this web application
     * @throws IllegalArgumentException If sessionTrackingModes specifies {@link
     * SessionTrackingMode#SSL} in combination with any other {@link SessionTrackingMode}
     * @throws IllegalStateException If the context has already been initialised
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public void setSessionTrackingModes(Set<SessionTrackingMode> sessionTrackingModes);

    /**
     * Obtains the default session tracking modes for this web application. By default {@link
     * SessionTrackingMode#URL} is always supported, {@link SessionTrackingMode#COOKIE} is supported
     * unless the <code>cookies</code> attribute has been set to <code>false</code> for the context
     * and {@link SessionTrackingMode#SSL} is supported if at least one of the connectors used by this
     * context has the attribute <code>secure</code> set to
     * <code>true</code>.
     *
     * @return The set of default session tracking modes for this web application
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public Set<SessionTrackingMode> getDefaultSessionTrackingModes();

    /**
     * Obtains the currently enabled session tracking modes for this web application.
     *
     * @return The value supplied via {@link #setSessionTrackingModes(Set)} if one was previously set,
     * else return the defaults
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public Set<SessionTrackingMode> getEffectiveSessionTrackingModes();

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param className TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public void addListener(String className);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param <T> TODO
     * @param t TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public <T extends EventListener> void addListener(T t);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param listenerClass TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public void addListener(Class<? extends EventListener> listenerClass);

    /**
     * TODO SERVLET3 - Add comments
     *
     * @param <T> TODO
     * @param c TODO
     * @return TODO
     * @throws ServletException TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0
     */
    public <T extends EventListener> T createListener(Class<T> c) throws ServletException;

    /**
     * @return TODO
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @since Servlet 3.0 TODO SERVLET3 - Add comments
     */
    public JspConfigDescriptor getJspConfigDescriptor();

    /**
     * Get the web application class loader associated with this ServletContext.
     *
     * @return The associated web application class loader
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws SecurityException if access to the class loader is prevented by a SecurityManager
     * @since Servlet 3.0
     */
    public ClassLoader getClassLoader();

    /**
     * Add to the declared roles for this ServletContext.
     *
     * @param roleNames The roles to add
     * @throws UnsupportedOperationException If called from a {@link ServletContextListener#contextInitialized(ServletContextEvent)}
     * method of a {@link ServletContextListener} that was not defined in a web.xml file, a
     * web-fragment.xml file nor annotated with {@link javax.servlet.annotation.WebListener}. For
     * example, a {@link ServletContextListener} defined in a TLD would not be able to use this
     * method.
     * @throws IllegalArgumentException If the list of roleNames is null or empty
     * @throws IllegalStateException If the ServletContext has already been initialised
     * @since Servlet 3.0
     */
    public void declareRoles(String... roleNames);

    /**
     * Get the primary name of the virtual host on which this context is deployed. The name may or may
     * not be a valid host name.
     *
     * @return The primary name of the virtual host on which this context is deployed
     * @since Servlet 3.1
     */
    public String getVirtualServerName();
}
